class Solution {
    public int search(int[] nums, int target) {
        int left = 0,right = nums.length - 1,mid = 0;
        while(left <= right) {
            mid = left + (right - left) / 2;//防止right+left的时候溢出
            if(nums[mid] == target) {
                return mid;
            }else if(nums[mid] < target) {
                left = mid + 1;
            }else {
                right = mid - 1;
            }
        }
        return -1;
    }
}